Study On Comprehensive Evaluation Method Of Pore Structure Of Tight Oil Reservoir

The tight oil reservoirs have poor physical properties and complex pore structure.It is difficult for reservoir classification.Therefore,the study on pore structure and classification method is of great significance to the exploration and development of tight oil.This paper took the tight sandstone of Chang-7 formation in Erdos basin as research object and took advantage of mercury injection experiment and nuclear magnetic resonance experiment to study the pore structure of cores and classification method.The paper used nonlinear method to transform the NMR T₂ spectrum into the capillary pressure curve,then the experiment data were used to test the transformation result.The result showed that the JSDR method was effective and met the requirement of accuracy.After analyzing the relationship between the measured pore structure parameters and the permeability,desirable parameters,porosity,geometry average value of NMR logging T₂ were used to construct the reservoir quality factor.The factor was used to classify cores and the reservoir and good result were obtained.In order to apply the factor to the survey region,the BP neural network was established between the conventional logging data and the quality factor.Then the model was applied to predict result using conventional logging data.The prediction was consistent with the test result and the effectiveness of the method was confirmed.